3 piece slate warp

afss

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Got the table i purchased pulled apart and the glue cleaned off the table. The slate is 3/4 inch. Two of the pieces seem pretty dead on, but one piece is out approx 1 mm in the center. its dead flat side to side all the way along it but across the short distance of the piece there is a belly in it that runs the width of it. Its pretty consistent at about 1mm. Can i do anything about this or am i screwed?

Each piece of slate is supported at two ends. This belly or sag is pretty well in the middle of the two supports. I was thinking maybe a third support in the middle???? Hope there is something i can do.
 
slate

You should be fine...you have to manipulate the slate...it takes a skill but I think we or I can help you..
How soon you ready to install?
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Rob.M
 
The table is on a floating laminate floor.

I have the frame re assembled.

I shimmed it as close to level as i could get being very tedious about it. I then took the frame and laid it on its side and glued and brad nailed the shims to the bottom of the legs and glues some rubbery non slip pads to that. Put the frame back in place and re checked, all was good.

Set the 3 pieces of slate on the frame and shimmed with cards. The weight of the slate changed my shiming as it sank the floor ( i think) so i have no cards at one end and up to 7 cards ( approx 2mm ) at the other end.

The piece i am concerned with has no cards at one end and 5 at the other. If i measure from the main support rail i get approx 1 mm of sag in the middle of this piece... I will try to post a sketch later as i think it may clarify what i am saying.

Thanks
 
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pooltablelayout.jpg


here is a general sketch of the lay out. The slate pieces 2 and 3 are flat or damn near flat in all directions. The piece number 1 is flat on the sketch top to bottom but not side to side as indicated by the numbers. 0 is level/flat, the negative numbers represent an approximate deflection from flat with the negative representing below flat.

Blue represents the slate pieces, red the frame and carying beams, black the legs.

Thanks
 
pooltablelayout.jpg


here is a general sketch of the lay out. The slate pieces 2 and 3 are flat or damn near flat in all directions. The piece number 1 is flat on the sketch top to bottom but not side to side as indicated by the numbers. 0 is level/flat, the negative numbers represent an approximate deflection from flat with the negative representing below flat.

Blue represents the slate pieces, red the frame and carying beams, black the legs.

Thanks

Try laying a 4ft. level on edge across where the sag is and looking at the light then using a very thinnly shaved angle wedge between the slate and frame in the middle from end of peice to center on both sides very slowly and hoplefully you will watch the light disappear.
 
You should be fine...you have to manipulate the slate...it takes a skill but I think we or I can help you..
How soon you ready to install?
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Rob.M


ready any time, felt should be here in a few days but i am not in a rush.. also was just thinking about it. While i had the table apart i had the slate leaning against a wall with radiant heat. I doubt its what caused it but figured i should mention it. the piece that seems to have the sag is the piece that was against the wall, nearest the radiator (hot water base board). It was there for approximately 3 weeks.
 
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Try laying a 4ft. level on edge across where the sag is and looking at the light then using a very thinnly shaved angle wedge between the slate and frame in the middle from end of peice to center on both sides very slowly and hoplefully you will watch the light disappear.

OK, so if i understand you correctly i would put a shim under the slate on the main carying beams A & B midway between C&D approximately directly above the legs which is approximately where the greatest deflection is?

Only problem here is that the main carying beams A and B are approximately 64-65 mm below the slate. Should i install a 3rd beam at this location between C&D approx 64 mm thick and shim from it?
 
OK, so if i understand you correctly i would put a shim under the slate on the main carying beams A & B midway between C&D approximately directly above the legs which is approximately where the greatest deflection is?

Only problem here is that the main carying beams A and B are approximately 64-65 mm below the slate. Should i install a 3rd beam at this location between C&D approx 64 mm thick and shim from it?

Yes a very thin shim between c & d between slate and a & b and hit very slowly no need for extra beam just put them where the frame is
 
Yes a very thin shim between c & d between slate and a & b and hit very slowly no need for extra beam just put them where the frame is


Beam A&B are 65-64 mm belo the slate surface so i will have to build it up some how. I got the gist of it. The slate currently is not screwed down yet. Should i screw it down and then try this, or do this and the screw it down?

The slate sits on beams C,D,E&F those beams sit on A&B
 
Beam A&B are 65-64 mm belo the slate surface so i will have to build it up some how. I got the gist of it. The slate currently is not screwed down yet. Should i screw it down and then try this, or do this and the screw it down?

The slate sits on beams C,D,E&F those beams sit on A&B

Ok. Imperial or Kasson it sounds like. so yes fill in the open space between crossbeams so you would then have a place to put the shims.
 
The only thing i can find on the table is a sticker on the warped piece of slate and i think it says BCE on it

Should i screw the slate down before or after this shimming?

Thanks for the help too.
 
slate

Allways screw the slate down tight before shiming to get a read on the table....you are prob gonna have the best luck with wood wedge shims to level slate....the problem you have ran into is the norm,like shane said..."Use shims" sand the tip of the shim to get in tight spots...
It is important where u place your shims near the screws..
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Have a nice day
Rob.M
 
Wanted to first say thanks to dontlitethat for calling me up and spending a good amount of time going over some of the basics to get me headed in the right direction. I am now on the hunt for a good level and although i doubt its top quality what do you want to achive when leveling a slate. The level i was looking at says it is good for 0.0005 inch per inch.
 
level

The last level you want to use is the one you are talking about .OOO5 is way over kill and you will pull your hair out by the roots trying to use the starett master 99Z level for slate leveling...use a starrett model 97 or 98..
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I'm gonna post a pic of the level models that you should use.
 

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That's .0005 per inch, so it would give you about .006 over 12 inches. Or around 1/32 over the span of the table. I actually didn't think it would be accurate enough.
 
Ok, I borrowed a machinists level, was going along great till I tried to level the piece with the warp. I can't seem to get the warp out. I think that rails A+B from the sketch are deflecting. I placed an additional rail between C+D at the point of max deflection and shimmed it.
What's the best way to remedy this? I assume by bracing the main carry beams to stop deflection? Would telesbar (the stuff road signs are on) work? Or 2 inch flat stock?
Thanks
 
That's .0005 per inch, so it would give you about .006 over 12 inches. Or around 1/32 over the span of the table. I actually didn't think it would be accurate enough.

That's .0005 per foot of elavation increase, not per inch;)
 
Actually the carpenters level that I was refering to in that post is 0.0005inches per inch which is 0.006 per foot just as I said.
The starret levels or machinists level is as you state.

What about my reienforceing question? Any info there?
 
You are probably looking at the milling tolerance of the carpenters level? It would take 4 lines out on my Starrett 12" before you could even see the bubble moved on the 4ft carpenters level. This wouldn't be one of the blue aluminum ones from HomeDepot would it?

The Starrett #98 is a 12" level with 0.005 graduations, more than accurate enough. In fact on most slate you will only be able to get it only as level as it was manufactured. Flat is a theory in manufacturing, there is no zero.

Rob
 
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